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'tlNTTao STATES PATEwTT EDW IN J. \VATSON AND HORACE \V. \VILLSON, OF \VOltGESTER, MASS.

PROCESS OFYPREPARING STEEL FOR WATCH=SPRINGS.

SPECIFICATION forming part of Letters Patent No. 252,635, dated January 24, 1882:

Application filed July 27, 1881. (No specimens.)

To all whom it may concern:

Be it known that we, EDWIN J. \VATsON and HORACE W. WILLsoN, both of the city and county of \Norcester, and Commonwealth of Massachusetts, have inv'entrd a' new and useful Process of Preparing Wire or Flat Strips of. Metal for Watch, Eyeglass, or other Springs; and we do hereby declare that the following is a full, clear, and exact description of the same.

The nature of our-invention consists in first taking-the metal of any given size suitable for making the springs and polishing it by any wellknown process, said metal having been previously partially hardened and tempered. .It is then reduced to the exact s ze required for the finished springs and again polished, thereby condensing or refining the metal and imparting to it the required high polish or finish necessary in this kind of springs. It is now rctempered by subjecting it to a proper heat and then immersing it in a bath of ether or ammonia, which process imparts to the metal a great degree of strength and elasticity, (in connection with the reducing and polishingprocesses,) and at the same time gives to the metal the required color, which may vary from a light-straw to a darkblue color, as will be hereinafter more fully set forth.

in carrying out our invention we first take the hardened and tempered steel of a size several degrees thicker than it is to be when finished. We then give it a high polish upon all sides by any suitable and well-known method, after which it is reduced to the required size, either by rolling or hammering. Although said reducing process somewhat diminishes the elasticity of the metal for the time being it so refines and compresses it that it is thereby rendered very tough and strong, and itis not ma- 4 terially changed from this consistency by the process of restoring it to its required temper and color, as hereinafter describt d. The metal, after having been polished and reduced in size to condense or refine the same, as aforesaid, is tempered so that it will possess more than its original elasticity, or sufficient to produce a very strong and elastic spring, by exposing it to sufficient heat to obtain the required color and then cooling it in a bath ofethcr or am1no-' nia, either of which will temper it to its proper consistency. This we have ascertained to be the case by actual practical tests. We have also found in the same manner that the aforesaid process of polishing, reducing, and tempering the partially-tempered steel (which is its consistency when submitted to our new process) imparts to thefinished springs the proper amount of strength and elasticity (as well as color) required for the purposes they are intendedviz., for watch, eyeglass, and other springs requiring great strength and elasticity. \Vc havefound inv practice that the color of the springs may be varied from a light straw to a. deep dark blue, as desired.

It'will be seenfrom the foregoing description that our aforesaid new process is exactly the reverse of any other now in use in the manufacture of steel wire or strips for watch and eyeglass springs.

By the old methods the steel is first rolled to the proper thickness in strips about fifty or sixty feet long and about three or four inches wide. It is thendivided into narrow strips and cut of the required lengths. The edges and surfaces are then finished and made of uniform size, after which said narrow strips are then hardened. The temper is then drawn enough to allow of their being worked without breaking, when they are again put through a polishing process and brought to a very high finish. Having been polished, the temper is again lowered or drawn and the required color obtained. Great difficulty is experienced in heating and hardening the steel by the aforesaid old processes, inasmuch as it has to be transferred from the fire to the cooling-bath very quickly or it will cool enough, if exposed to the air an instant too long, to preventits hard ening uniformly. Various expedieuts are resorted to to prevent this withniore or less success; but the strips are so thin that with all the care that can be given to them many of the springs are useless, some being too hard, others too soft. These processes, as far as we can ascertain, are all performed by hand that is, the different springs or short sections of strips are handled separately or a very few at a time in polishing, tempering, and coloring the same.

By our process it will be seen that the temper is raised instead of lowered or drawn as by l'OO the old processes in coloring, the advantage of which is obvious to all who are skilled in the art to which our invention appertains.

Another and very important advantage of our process over the old, in addition to prod uc ing a much stronger and more elastic spring, is the rapidity with which the strips may be prepared and the springs formed from the same. By our method the steel is taken in coils weighing from five to twenty pounds, measuring from two to five hundred feet to the pound, (or of greater weight and longer lengths, if desired,) and continuously passed through the several stages of our aforesaid new process, hereinbefore described, by suitable automatic machinery prepared for the purpose, and after having been so prepared it is cut into short sections, and said sections bent to form the springs continuously by still other automatic machinery described and claimed in a separate application for Letters Patent. It will therefore be seen that the afore said process is very expeditiously performed, one man being enabled todo the work of several by the old process. A much softer grade of steel may also be used, as it tends to improve and refine the metal.

It will be observed that if by any mischance the steel should be overheated in theprocess of tempering, our method of reducing by rolling or hammering, as aforesaid, restores it to nearly its original quality, and by polishing it after it is hardened and tem ered and before Having thus described our new process of 5 preparing wire or flat strips of metal for watch, eyeglass, and other springs, what we claim therein as new and of our invention, and desire to secure by Letters Patent, is-

The process of preparingpartially hardened and tempered steel for watch, eyeglass, and other springs by first polishing the same when of a size .several degrees larger in cross-section thauit is required to be when finished, then reducing it to the proper finish size by rolling, hammering, or otherwise, and polishing it, and afterward tempering and coloring the same by first exposing it to suflicient heat to obtain the required color, and imlnersingit in a cooling or tempering bath of ether or ammonia, substantially as described.

EDWIN J. WATSON. HORACE W. WlLLSON. Witnesses:

- WALTER B. NoURsE, ALBERT A. BARKER. 

